In a fluid control apparatus used in a semiconductor production apparatus, integration has been advanced in such a manner that a line is formed by arranging a plurality of fluid control devices in series and connecting them without using a pipe or a connector, and a plurality of such lines are installed in parallel on a base member (Patent document 1 and Patent document 2).
In a fluid control apparatus of Patent document 1, as shown in FIG. 7, one process gas control line (fluid control line) is formed of one flow rate controller (21) serving as a basic constituting element, and a plurality (the same number as that of flow rate controllers (21)) of process gas control lines L1 to L16 are arranged in parallel to form the fluid control apparatus. The line P further added to the fluid control lines L1 to L16 in parallel is a purge gas line.
In FIG. 7, each of the process gas control lines L1 to L16 has a filter (24), two inlet-side on-off valves (23) on the inlet side, a flow rate controller(mass flow controller) (21) and an outlet-side on-off valve (25) from the inlet side, and an outlet part that is common to the process gas control lines L1 to L16 is also provided with an on-off valve (26).
In such a fluid control apparatus, fluid (gas) does not constantly flow through all the process gas control lines L1 to L16, and gas is conveyed to a downstream chamber while gases of different kinds or different flow rates are sequentially varied using 2 to 3 lines, and the flow rate is adjusted by a flow rate controller (21). The mass flow controller used as the flow rate controller (21) incorporates a flow rate sensor, a control valve and the like, and requires expensive and frequent maintenance, leading increase in the overall cost. On the other hand, in a fluid control apparatus used in a semiconductor production apparatus, the trend of increase in number of kinds of fluids leads the problem of increase in space and cost.
A fluid control apparatus of Patent document 2 has a fluid controlling unit in which M fluid control lines each having a flow rate controller as a basic constituting element, one inlet, and one outlet are arranged, and a fluid introducing unit formed of a plurality of on-off valves so that the number of inlets is N (>M) and the number of outlets is M, wherein M outlets of the fluid introducing unit and M inlets of the fluid controlling unit are one-on-one connected.
Assigning the apparatus of Patent document 2 to the conventional fluid control apparatus shown in FIG. 7, it has a fluid controlling unit (2) in which M (8 in the drawing) fluid control lines L1 to L8 each having the flow rate controller (21) as a basic constituting element, and a fluid introducing unit (3) formed of a plurality of on-off valves (23) so that the number of inlets is N (16 in the drawing) and the number of outlets is M as shown in FIG. 6.
In the same drawing, each of the fluid control lines L1 to L8 is a line of controlling process gas, and one purge gas line P is provided in parallel with these.
As a flow rate controller (21), a mass flow controller is used. Since the mass flow controller (21) has relatively narrow flow rate adjustable range, even for the same kind of fluid, a separate mass flow controller (21) is used when the flow rate adjustment range differs, and flow rates of M kinds of process gases (including the same process gas with different flow rates) can be adjusted by means of the M fluid control lines L1 to L8.
The fluid introducing unit (3) includes N×M on-off valves (23), and the M outlets of the fluid introducing unit (3) and the M inlets of the fluid controlling unit (2) are connected one-on-one.
Each of the N inlets of the fluid introducing unit (3) is provided with the filter (24) and a manual valve (27). Each of the M fluid control lines L1 to L8 is provided with two outlet-side on-off valves (25). On the outlet side of the fluid controlling unit (2), a pressure switch (28), the filter (24), and the on-off valve (26) that are common to the fluid control lines L1 to L8 are provided.
As the flow rate controller, besides the mass flow controller, a pressure type is also known (see Patent document 3 for reference).    Patent document 1: Japanese Unexamined Patent Publication No. 2002-206700    Patent document 2: Japanese Unexamined Patent Publication No. 2000-323464    Patent document 3: Japanese Patent Publication No. 3387849